No straight line, and Brush Size incorrect

So I am having some issues with GIMP. I have followed all the videos, I even rewatched the video on higher resolution to make sure I didn’t miss anything… so, I’m not sure what the problem is.

  1. I have set my New settings as described in the video to 32x32px, and the DPI is 72x72. I have selected the Hardness 075 brush (though the same thing happens with any other brush), and have set the size to 1… It does nothing, it does not change the pixel it is hovering over… But if i increase the size to 10, it works coloring 1 pixel at a time ( i assume)… but it acts the same if increase the size, even to 50 before the color starts appearing bigger.
  2. When I click to color a pixel and then hold shift… nothing happens. I dont get a line visible and if i move my mouse, it just colors random pixels, not in a straight line.
    Am I missing some setting or something?